For instance, in A/V (AudioVisual) appliances such as television receivers, VTRs, and CD players, and also, in various sorts of electronic appliances such as air conditioners and lighting equipments, infrared communications is widely utilized as wireless communications. In infrared communications, signals are transmitted/received by operating infrared communication apparatuses which are provided in main appliances (television receivers etc.) and counter appliances (infrared remote controllers etc.) (refer to, for example, Patent document 1).
As shown in FIG. 1, such an infrared communication apparatus 1 is arranged by a transmitting/receiving unit 3 and a control unit 5.
The transmitting/receiving unit 3 is arranged by a light emitting unit 11 and a light receiving unit 17. The light emitting unit 11 is constituted by an LED 7 and an LED driver 9. The light receiving unit 17 is constituted by a photodiode 13 and a reception amplifier 15. Also, the control unit 5 is arranged by a modulator 19 and a demodulator 21. The modulator 19 modulates transmission data so as to transfer the modulated transmission data to the light receiving unit 11. The demodulator 21 demodulates a signal received by the light receiving unit 17 and converts the demodulated signal into reception data.
Such an infrared communication apparatus 1 is operated as follows: That is, the transmission data is modulated by the modulator 19 in a pulse-width modulating method. Thereafter, the pulse-width modulated transmission data is transferred to the LED driver 9 so as to be converted into an optical signal by the LED 7. On the other hand, an optical signal transmitted from a communication counter unit is converted into an electric signal by the photodiode 13. Thereafter, the converted electric signal is amplified by the reception amplifier 15, and the amplified signal is demodulated by the demodulator 21, and then, the demodulated signal is outputted as reception data.    Patent document 1; JP-A-6-303452